1. Field of the Invention
The present invention relates to riveting devices and more particularly to a pneumatic impact gun designed to upset conventional rivets in a single impact. The majority of pneumatic impact guns presently marketed require that a plurality of impacts be effectuated in order to upset a rivet. Such a plurality of impacts is undesirable for several reasons. First of all, attendant noise levels are often objectionable. For instance, the Federal Government's office of Safety and Health Administration has promulgated standards in order to reduce noise levels in factories and other industrial areas.
Furthermore, a lightweight pneumatic gun which upsets rivets in a single impact would greatly reduce the time required in the aircraft industry to rivet component sheets of a fuselage, wing skin, etc. In order to provide a lightweight pneumatic single impact riveting gun, the present invention contemplates the use of novel accumulator arrangement which will rapidly discharge or dump stored compressed air into a cylinder for actuation of a piston which will strike an anvil. The anvil impacts a rivet shank with sufficient energy to upset or form a button on the rivet in a single impact.
2. Description of the Prior Art
The Boeing Company has utilized pneumatic impact guns for many years, but there has not been a sufficiently lightweight single impact riveting gun until the present invention. In U.S. Pat. No. 3,559,269 by H. A. Schmitt et al, there is disclosed a high impact portable riveting apparatus. This patent provides for a sufficiently adequate single impact riveting apparatus but requires the use of complex and expensive electric circuitry in order to adequately function. It is readily apparent that the present pneumatic impact system utilizing a lightweight gun sufficiently powerful to upset standard rivets in a single impact is greatly advantageous to the apparatus disclosed in the aforementioned patent.